Flower in harvest moon back to nature?

Not sure what you're asking exactly so I hope this helps:

You can buy flour from the supermarket for cooking with.

You can buy flower seeds to plant from Won at the Inn, just make sure to check which season to plant them in first.

If you grow 90 flowers at onetime Manna will give you a power berry

There is a special flower you'll see the first time you go to the mountain top on a snowy night. This event automatically puts you to sleep and the next day you should tell Basil and Ellen about it. This event is triggered even on festivals, so if you plan on going to the New Years Eve festival I'd advise getting this out of the way.

Popuri's father has left the town to find a special "Dessert Flower" for Popuri's mother, Lilia. This is often referenced by the towns people.